A farm has been fined £10,000 for causing an environmental catastrophe which wiped out fish and insect life along 20 kms of a Sussex river.

The strawberry farm near Uckfield was in the process of going organic and in its last season using pesticide when the spillage occurred.

A powerful chemical leaked from a faulty pump on the Working Wonders Farm into the Pellingford Brook tributary at Sheffield Park and into the River Ouse, destroying up to 80 per cent of the fish population.

Farm bosses were shocked to discover their operation was the source of the pollution after using the same process without incident for 20 years.

The company pleaded guilty to causing pesticide to enter controlled waters and was sentenced at Lewes Crown Court on Friday.

After being fined £10,000, farm director Paul Cragg called on the Government to ban powerful pesticides to prevent future environmental catastrophes.

The Environment Agency was alerted when anglers started reporting dead and distressed fish in the Ouse in August 2001.

Their investigations identified the pollutant as a pesticide with the trade name Dursban and traced the source to the farm at Sheffield Park.

The chemical had been used on the strawberry crop in an attempt to control vine weevil on the fruit.

Further investigations revealed the likely source of the spillage was an irrigation pump or filter.

The farm, which is now fully organic, was "extremely embarrassed" about the whole incident.

The Environment Agency accepted the pollution was accidental and that the farm was "well managed".

However, experts believe the river will not fully recover until August, two years after the incident.

Gary Lucie, prosecuting, told the court the river provided drinking water for the Lewes area and residents had feared their supplies might have been polluted.

But he said the pesticide was treatable and not a threat to the health of humans.

Gareth Rees, defending, said: "The company entirely accepts it was the cause of this terrible incident. the result was shocking.

"At the same time there is a huge difference in offences where it is quite clear that companies or individuals turn a blind eye and even sometimes deliberately cause pollution.

"This is the other end of the spectrum.

"There was no skimping as far as this company was concerned - in fact quite the opposite. This company has a very good record on environmental matters. It was an isolated incident.

"The company was well on its way to becoming organic but what it has discovered is that this chemical is still being recommended for use on this virulent bug. If the Government approves its use as it does, this is the risk."

Judge Niblett fined the firm £10,000 and ordered it to pay £3,291 costs.

Adding £12,000 Working Wonders owes the Environment Agency for the clean-up operation and its £10,000 legal fees, the company faces an overall bill of £35,000.

Describing the incident as "nothing short of catastrophic" the judge said he accepted the pollution was not deliberate and the firm had shown a high degree of responsibility before and after the incident.

Outside court, Mr Cragg called on the Government to ban powerful pesticides or run the risk of future environmental catastrophe.

He said: "We don't need a lesson in the dangers of chemicals because we have moved out of them but society needs a lesson.

"These chemicals should be banned outright."